Software controlled gear change mechanism for a motor vehicle

ABSTRACT

The present invention relates to a gear control of a motor vehicle. The gear control incorporates a gear lever ( 1 ) which can be placed in at least two mutually spaced gear positions (V 1-5 ), each of which initiates a particular gear change in a gearbox ( 12 ). The gear control incorporates at least one power device ( 4 ) connected to the gear lever ( 1 ), a position reader ( 7-10 ) designed to detect the position of the gear lever ( 1 ), and a control unit ( 11 ) designed to control the power device ( 4 ) on the basis of the position of the gear lever ( 1 ) so that movements of the gear lever ( 1 ) are only allowed along a particular path ( 3 ) which is defined by a control unit ( 11 ) containing software.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a gear control of a motor vehicle usable withsubstantially all types of gear boxes, and which imparts the same gearchange sensation when used with semi-automatic gear controls as withmanual gear controls, but occupies substantially the same space as asemi-automatic gear control.

2. Relevant Art

Manual gearchanging on a motor vehicle is usually initiated by a gearcontrol which is arranged in a driver's cab in the vehicle. The gearcontrol generally incorporates a gear lever which the driver can movealong a path in order to place it in the desired gear position. The pathis defined by a control gate. A mechanical shaft transmits the movementsof the gear lever to the gearbox. Alternatively a flexible wire maytransmit the movements of the gear lever to the gearbox. Such mechanicaltransmissions occupy a relatively large amount of space. Factors such asthe presence of said control gate make it necessary to use a gearcontrol which is specifically suited to the particular type of gearboxfitted to the vehicle.

Semi-automatic gearchanging on a vehicle is usually likewise initiatedby means of a gear lever. In this case the driver can initiate agearchange by moving the gear lever to a desired gear position or by agearchange-indicating movement of the gear lever. An electrical signalis then transmitted from the gear control to the gearbox, whereupon thedesired gear is engaged. This means that there is no need for anyspace-occupying mechanical transmission to transmit the movements of thegear lever to the gearbox. A clutch pedal will generally also besuperfluous. It is difficult, however, for the driver to have the samegearchange sensation with such a semi-automatic gear control as with amanual gear control.

SUMMARY OF THE INVENTION

An object of the present invention is therefore to provide a gearcontrol which can be used for substantially all types of gearboxes. Afurther object is to provide a gear control which imparts the samegearchange sensation as a manual gear control while at the same time notoccupying substantially more space than a semi-automatic gear control.

The aforesaid objects are achieved by a gear control including a gearlever, at least one power device connected to the gear lever, a positionreader designed to detect the position of the gear lever, and a controlunit designed to control the power device on the basis of the positionof the gear lever so that movements of the gear lever are only allowedalong a particular path which is defined by software incorporated in thecontrol unit. The fact that the control unit controls said power deviceso that movements of the gear lever are only allowed along a particularpath results in the same function as with a control gate. Arrangingsuitable software in the control unit makes it possible to obtainsubstantially all types of paths and to have substantially any desiredlayout of gear positions. This means that the same gear control can beconnected to a gearbox of substantially any desired type simply byappropriate change of software in the control unit.

According to a preferred embodiment of the invention, said power deviceis variable in length and a first end of it is connected to the gearlever and a second end of it is connected to a static structure in thevehicle. The ability of such a power device to change its length can becontrolled to block movements of the gear lever outside said particularpath but to allow movements within the extent of the path.Alternatively, said power device may be rotatably connected to the gearlever. In that case the power device is connected to a substantiallyimmovable lower portion of the gear lever. The rotary movements of sucha power device can be controlled to block movements of the gear leveroutside said particular path but to allow movements within the extent ofthe path. It is advantageous that a first power device be designed tosubstantially limit movements of the gear lever in its first directionand that a second power device be designed to substantially limitmovements of the gear lever in a second direction which is substantiallyperpendicular to the first direction. As conventional gear levers are inprinciple movable in two mutually perpendicular directions, such adesign results in relatively uncomplicated control of the gear lever.Such a design also results in stable control of the movements of thegear lever along said path. It is advantageous that each of said powerdevices be designed to be activated by an electric motor. Using electricmotors makes it possible to give the power devices a short reaction timeand the necessary force for preventing movement of the gear leveroutside said path. Alternatively, suitable pneumatic or hydraulic powerdevices may be used.

According to a second preferred embodiment of the invention, saidposition reader is optical. An optical position reader enables theposition of the gear lever to be read with great accuracy withoutaffecting the movements of the lever. Such a sensor may incorporate onthe gear lever a diode which transmits an infra-red light beam towards aphotosensitive detector which has a fixed position in the vehicle.Alternative position readers may be resistive, capacitive, inductive ormagnetic. When the gear lever is moved to one of said gear positions,the control unit is designed to send a signal to the gearbox in order toinitiate engagement of the gear which corresponds to the gear positionof the gearbox. Such a signal is with advantage electrical and reachesthe gearbox via an electric cable. Arranging an electric cable betweenthe gear control and the gearbox requires very little space comparedwith a mechanical transmission.

According to another preferred embodiment of the present invention, saidpower devices are designed to indicate to the driver when the gearcontrol is in/out of said gear positions. To enable the driver to feelby hand when the gear lever reaches a gear position, said power devicesmay create an increased non-rigid resistance shortly before the gearlever reaches the relevant gear position. Suitable software in thecontrol unit makes it possible to increase the gearchange sensationfurther by giving said power devices different functions depending onthe position of the gear lever along said path. The power devices mayfor example transmit springing, damping, pulsating or vibrating forcesto the gear lever.

According to another preferred embodiment of the present invention, thecontrol unit is designed to prevent the gear lever being moved to one ormore of said gear positions during certain operating states of thevehicle. Depending on various parameters such as, for example, the speedof the vehicle, the engagement of certain gears may be inappropriateand/or damaging to the vehicle's engine and driveline. The control unitcan thus prevent an incorrect gear being engaged by mistake.

According to another preferred embodiment of the present invention, oneof said gear positions involves activation of an automatic gearchangefunction. A vehicle with the gear control described above usuallyincorporates a gearchange mechanism which alters the gear ratio of thegearbox according to electrical signals received from the gear control.Having the control unit determine instead when gear changing should takeplace on the basis of information about parameters which are relevantfor changing gear is not very complicated. It is therefore an advantageif the driver has the possibility of moving the gear lever to a gearposition which initiates automatic gearchanging of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below by way ofexamples with reference to the attached drawings, in which:

FIG. 1 depicts schematically a manual gear control,

FIG. 2 depicts a gear control according to a first embodiment and

FIG. 3 depicts a gear control according to a second embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 depicts a conventional manual gear control. The gear controlincorporates a gear lever 1 which can be placed in a number of mutuallyspaced gear positions v₁₋₅. The gear control also incorporates a controlgate 2 which allows movements along a particular path 3 to said gearpositions v₁₋₅. The extent of such paths 3 is substantially standardisedin vehicles so that a vehicle driver knows exactly how to move the gearlever between the various gear positions v₁₋₅. The fact thatconventional gear controls usually incorporate such a control gate 2means that they are at least limited to being connectable to gearboxesthat have a number of gears (v₁₋₅) which corresponds to the control gate2.

FIG. 2 depicts a first embodiment of the present invention. In this casea gear lever 1 is viewed from above. A variable-length first powerdevice 4 and a variable-length second power device 4 which are ofsubstantially identical design each have a first end 4 a connected tothe gear lever 1 and a second end 4 b connected to a static structure 5in the vehicle. The ends 4 a, 4 b of the power devices 4 arearticulatedly connected at the fastening points. Each of the twovariable-length power devices 4 has its electric motor 6 which isdesigned to alter the length of the power devices 4. Suitable electricmotors 6 enable the power devices 4 to change length quickly and toexert a relatively large force. The two variable-length power devices 4are designed to act in a plane which is substantially perpendicular tothe main direction of extent of the gear lever 1. The power devices 4are variable in extent in directions which form an angle of about 90° toone another.

An optical position-reading arrangement incorporates a diode 7 which isarranged firmly on the gear lever 1. The diode 7 is designed to emit aninfra-red light beam 8 towards a photosensitive surface 9 which isincorporated in a photosensitive detector 10. The photosensitivedetector 10 emits a first current signal which is related to theincident light intensity and a second current signal which is related toa centre of the incident light. The position of the gear lever can thusbe determined with good accuracy. A control unit 11, which incorporatesreadily interchangeable software, is designed to activate and controlthe electric motors 6 and hence the power devices 4 on the basis ofknowledge of the position of the gear lever 1 so that the gear lever 1can only move along a particular path 3 to various gear positions v₁₋₅.The software in the control unit 11 can be changed to provide differentpaths for the same gear control. In FIG. 2, broken lines are used todepict such a path 3. Accordingly there is no need for any control gate2, since the software in the control unit 11 defines the extent of thepath. When the gear lever 1 is moved to one of said gear positions v₁₋₅,the control unit 11 is designed to send an electrical signal via anelectric cable to a gearbox 12. The gearbox 12 incorporates a gearchangemechanism which engages the gear which corresponds to the gear positionv₁₋₅ of the gear lever 1. This means that only an electric cable has tobe arranged between the gear control and the gearbox 12. Such a cableoccupies very little space. As the actual engagement of a new gear takesplace automatically, the vehicle needs no clutch pedal.

The control unit 11 receives from the position-reading arrangementsubstantially continuous information concerning the position of the gearlever 1. This enables the control unit 11 to activate the electricmotors 6 so that the power devices 4 exert maximum force to block suchdirections of movement of the gear lever 1 as do not follow the extentof the path 3. To enable a driver wishing to engage a different gear tofeel by hand when the gear lever 1 reaches a gear position v₁₋₅, thepower devices 4 create an increased non-rigid resistance when the gearlever 1 passes a short section substantially just before the gearposition v₁₋₅. To further increase the gearchange sensation, suitablesoftware may be used in the control unit 11 to make the power devices 4provide other functions depending on the position of the gear lever 1along said path 3. The power devices 4 may for example transmit a springforce, a damping force, a pulsating force or a vibrating force to thegear lever 1 to provide the driver with a corresponding gearchangesensation as in a manual gear control. In certain operating states ofthe vehicle, the control unit 11 is designed to prevent the gear lever 1being moved to one or more of the gear positions v₁₋₅. Depending onvarious parameters such as the vehicle's speed, the engagement of acertain gear may in certain situations be inappropriate and/or damagingto the vehicle's engine and driveline. The control unit 11 thus preventsan incorrect gear being engaged by mistake. One of said gear positionsv₁₋₅ may incorporate activation of an automatic gearchange function. Avehicle with the gear control described above thus incorporates alreadya gearchange mechanism which engages a desired gear on the basis of twosignals received from the gear control. Having the control unit 11determine instead when gear changing should take place on the basis ofinformation about parameters relevant to the gearchange process entailsno major modification. It is therefore an advantage if the driver isprovided with the possibility of moving the gear lever to such a gearposition v₁₋₅ which initiates automatic gearchanging of the vehicle.

FIG. 3 depicts an alternative embodiment of the present invention. Inthis embodiment, first and second power devices 4 are applied. Each ofthe power devices 4 incorporates an electric motor 6. Each of theelectric motors 6 has protruding from it a first shaft 13 which isprovided with a first sprocket 14. A chain 15 is designed to transmitthe motion of the first sprocket 14 to a second sprocket 16 which isarranged on a second shaft 17. The second shaft 17 is suitably fastenedto a lower portion of the gear lever 1. This lower portion of the gearlever 1 has a substantially immovable position. The second shafts 17 arearranged at a substantially right angle to one another. The gear lever 1may possibly be angled relative to its lower portion so that a portionsituated higher up of the gear lever 1 is arranged for movement alongthe path. A movable portion of the gear lever 1 incorporates a positionreader. The position reader incorporates in this case two diodes 7 whichare firmly arranged on the gear lever 1. Each of the diodes 7 isdesigned to emit an infra-red light beam 8 towards its respectivephotosensitive detector 10 which incorporates a photosensitive surface9. The position of the gear lever 1 can thus be determined in the twomain directions of movement of said lever. The control unit 11 isdesigned to receive information from the photosensitive detectors 10 inorder to activate and control the electric motors 6 on the basis ofknowledge of the position of the gear lever 1. When the gear lever 1 ismoved to a gear position, the control unit 11 is designed to send anelectric signal via an electric cable to the gearbox 12. The gearbox 12incorporates a gearchange mechanism which engages the gear whichcorresponds to the gear position v₁₋₅ of the gear lever 1. Each of theelectric motors 6 is in this case allowed to block or influencemovements of the gear lever 1 in its respective substantiallyperpendicular direction so that a movable portion of the gear lever 1 isonly arranged for movement along a path 3 which is determined by thesoftware in the control unit 11.

The gear controls described in FIGS. 2 and 3 afford the advantage ofbeing connectable to substantially all types of gearboxes 12irrespective of the number of gears. Adapting the gear control to adifferent type of gearbox 12 is achieved by simply replacing thesoftware of the control unit 11 by different software. It is alsopossible to use software which defines paths 3 which are suited to thewishes of individual persons.

The invention is in no way limited to the embodiments described but maybe varied freely within the scopes of the patent claims. For example,the electric motors 6 in FIG. 3 may by connected directly via theiroutput shafts to the lower portion of the gear lever 1 without anyintermediate transmission elements. Alternatively, the transmissionelements may be of substantially any functional kind desired and may bearranged between the output shaft 13 of the electric motor 6 and thelower portion of the gear lever 1.

It is intended therefore, that the present invention not be limited notby the specific disclosure herein, but to be given the full scopeindicated by the appended claims.

1. A gear control for a motor vehicle gear box comprising; anoperator-manipulated gear lever which can be placed in at least twomutually spaced gear positions, each of which initiates a particulargear change in the gearbox; a power device connected to theoperator-manipulated gear lever and operable to control movement of theoperator-manipulated gear lever alone a particular path; a positionreader operable to detect the position of the operator-manipulated gearlever; and a control unit including software responsive to the positionof the gear lever detected by the position reader, and the control unitis operative to control the power device on the basis of the detectedposition of the operator-manipulated gear to control the movements ofthe operator-manipulated gear lever to be only along a particular pathwhich is defined by the software included in the control unit.
 2. A gearcontrol according to claim 1, wherein the power device includes anelectric motor controlled by the control unit.
 3. A gear controlaccording to claim 1, wherein the power device comprises a first and asecond power device operatively connected to the gear lever to controlmovement thereof and wherein: the first power device is operative topermit movement of the operator-manipulated gear lever in a firstdirection; the second power device is operative to permit movement ofthe operator manipulated gear lever in a second direction which issubstantially perpendicular to the first direction; and the control unitis operative to control the first and second power devices such thatmovements of the operator-manipulated gear lever in the first and seconddirections are defined by the software included in the control unit. 4.A gear control according to claim 3, wherein the first and second powerdevices each include an electric motor.
 5. A gear control according toclaim 3, wherein the first and second power devices are variable inlength and include respective first ends connected to theoperator-manipulated gear lever and respective second ends connected toa static structure in the vehicle.
 6. A gear control according to claim1, wherein the power device is variable in length and includes a firstend connected to the gear lever and a second end connected to a staticstructure in the vehicle.
 7. A gear control according to claim 1,wherein the power device is rotatably connected to the gear lever.
 8. Agear control according to claim 1, wherein the position reader is anoptical device.
 9. A gear control for a motor vehicle gearboxcomprising; a gear lever which can be placed in at least two mutuallyspaced gear positions, wherein each of the positions initiates aparticular gear change in the gearbox; a first power device operativelyconnected to the gear lever and the first sower device being operativeto permit movement of the gear lever in a first direction; a secondpower device operatively connected to the gear lever and the secondpower device being operative to permit movement of the gear lever in asecond direction which is substantially perpendicular to the firstdirection: wherein the first and second power devices are operative toprovide an operator of the gear lever with a perceptible indication whenthe gear lever is moved into and out of at least one of the gearpositions; a position reader operative to detect the position of thenear lever; a control unit including software responsive to the positionof the gear lever detected by the position reader, and the control unitis operative to control the first and the second power devices on thebasis of the detected position of the gear lever to control themovements of the gear lever to be along a particular path which isdefined by the software included in the control unit.
 10. A gear controlaccording to claim 9, wherein each of the first and second power devicesincludes an electric motor.
 11. A gear control according to claim 9,wherein each of the first and second power devices is variable in lengthand each includes a respective first end connected to the gear lever anda respective second end connected to a static structure in the vehicle.12. A gear control according to claim 9, wherein at least one the powerdevices is rotatably connected to the gear lever.
 13. A gear controlaccording to claim 9, wherein the position reader is an optical device.14. A gear control for a motor vehicle near box comprising: a gear leverwhich can be placed in at least two mutually spaced near positions, andeach position initiates a particular sear change in the gearbox; a powerdevice connected to the gear lever and operable to control movement ofthe gear lever along a particular path; a position reader operable todetect the position of the gear lever; and a control unit includingsoftware responsive to the position of the gear lever detected by theposition reader, and the control unit is operative to control the powerdevice on the basis of the detected position of the gear lever tocontrol the movements of the gear lever to be only along a particularpath which is defined by the software included in the control unit.wherein the control unit is responsive to selection of a gear positionby the gear lever to send a signal to the gearbox to initiate engagementof a gear corresponding to the selected position.
 15. A gear control fora motor vehicle gear box comprising: a gear lever which can be placed inat least two mutually spaced gear positions, and each position initiatesa particular gear change in the gearbox; a power device connected to thenear lever and operable to control movement of the gear lever along aparticular path; wherein the power device is operative to provide adriver of a vehicle with a perceptible indication when the gear lever ismoved into and out of a gear position; a position reader operable todetect the position of the gear lever; and a control unit includingsoftware responsive to the position of the gear lever detected by theposition reader, and the control unit is operative to control the powerdevice on the basis of the detected position of the gear lever tocontrol the movements of the gear lever to be only along a particularpath which is defined by the software included in the control unit. 16.A gear control for a motor vehicle gear box comprising; a near leverwhich can be placed in at least two mutually spaced near positions, andeach position initiates a particular gear change in the gearbox: a powerdevice connected to the gear lever and operable to control movement ofthe gear lever along a particular path; wherein the control unit isoperative to prevent the gear lever from being moved to one of the gearpositions during certain operating states of the vehicle; a positionreader operable to detect the position of the gear lever; and a controlunit including software responsive to the position of the sear leverdetected by the position reader, and the control unit is operative tocontrol the power device on the basis of the detected position of thegear lever to control the movements of the gear lever to be only along aparticular path which is defined by the software included in the controlunit.
 17. A gear control for a motor vehicle gear box comprising: a gearlever which can be placed in at least two mutually spaced gearpositions, at least one of the positions initiates a particular gearchange in the gearbox and wherein one of the gear positions activates anautomatic gear change function; a power device connected to the gearlever; a position reader constructed to detect the position of the nearlever; and a control unit including software responsive to the positionreader, and the control unit is operative to control the power device onthe basis of the position of the near lever such that movements of thegear lever are only allowed along a particular oath which is defined bythe software included in the control unit.